The Gale Encyclopedia of Neurological Disorders vol 2 - part 5 pps

702
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
Progressive multifocal leukoencephalopathy
PERIODICALS
Horwich, A. L., and J. S. Weissmann. “Deadly
Conformations—Protein Misfolding in Prion Disease.”
Cell 89 (1997): 499–510.
Mastrianni, J. A., M. T. Curtis, et al. “Prion Disease (PrP-
A117V) Presenting with Ataxia Instead of Dementia.”
Neurology 45, no. 11 (1995): 2042–2050.
OTHER
Biosafety in Biomedical and Microbiological Laboratories.
The Prion Diseases. BMBL Section VII-D Table 1,
National Institutes of Health.
Centers for Disease Control and Prevention. Bovine
Spongiform Encephalopathy Detected in Canada. Articles
(2003).
Centers for Disease Control and Prevention. BSE and CJD
Information and Resources. Bovine Spongiform
Encephalopathy Main Index (2003).
Centers for Disease Control and Prevention. “Creutzfeldt-
Jakob Disease Associated with Cadaveric Dura Mater
Grafts.” Morbidity and Mortality Weekly Report (1997)
46(45): 1066–9.
Centers for Disease Control and Prevention. Fact Sheet: New
Variant Creutzfeldt-Jakob Disease. Articles (2003).
Centers for Disease Control and Prevention. Preliminary
Investigation Suggests BSE-Infected Cow in Washington
State Was Likely Imported from Canada. Articles (2003).
Centers for Disease Control and Prevention. Questions and
Answers Regarding Bovine Spongiform Encephalopathy

(BSE) and Creutzfeldt-Jakob Disease (CJD). Articles
(2003).
Centers for Disease Control and Prevention. Questions and
Answers Regarding Bovine Spongiform Encephalopathy
in Canada. Articles (2003).
Centers for Disease Control and Prevention. Questions and
Answers Regarding Creutzfeldt-Jakob Disease Infection-
Control Practices. Articles (2003).
Centers for Disease Control and Prevention. Update 2002:
Bovine Spongiform Encephalopathy and Variant
Creutzfeldt-Jakob Disease. Articles (2002).
Creutzfeldt-Jakob Disease Foundation Inc. Creutzfeldt-Jakob
Disease. CJD Info.
Creutzfeldt-Jakob Disease Voice. Creutzfeldt-Jakob Disease
Fact Sheet. CJD Info.
FDA Press Office. FDA Prohibits Mammalian Protein in
Sheep and Cattle Feed. FDA Talk Paper (1997).
Heaphy, S. Prions and BSE. University of Leicester, UK: BSE
Risk Assessment (2004).
Kimball, John W., PhD. Kimball’s Biology. 2003 (March 23,
2004). Online textbook <o>.
Meikle, James. Anger at Two-year Delay in CJD Drug Tests.
The Guardian UK (2003).
Sander, David M., PhD. Prion Diseases. Virology Course 335
(1999), Tulane University.
Schonberger, Lawrence, and Ermias Belay. Bovine Spongiform
Encephalopathy and Variant Creutzfeldt-Jakob Disease.
Centers for Disease Control and Prevention Travelers’
Health Information (2003-2004).
UCSF Today Two Old Drugs May Help Fight Prion Disease.

University of California San Francisco.
Veneman, Ann M. Statement Regarding Canada’s
Announcement of BSE Investigation. USDA Statement
No. 0166.03 (2003).
ORGANIZATIONS
Centers for Disease Control and Prevention. 1600 Clifton
Road, Atlanta, GA 30333. (404) 639-3534 or (800) 311-
3435. <>.
CJD Foundation, Inc. P.O. Box 5313, Akron, OH 44334, (330)
665-5590 or (800) 659-1991; Fax: (330) 668-2474.
<>.
National Organization for Rare Disorders. 55 Kenosia Avenue,
P.O. Box 1968, Danbury, CT 06813. (203) 744-0100 or
(800) 999-6673; Fax: (203) 798-2211. orphan@
rarediseases.org. <>.
National Prion Disease Pathology Surveillance Center. Case
Western Reserve University 2085 Adelbert Road, Room
418, Cleveland, OH 44106. (216) 368-0587; Fax: (216)
368-4090. <>.
National Institutes of Health. 9000 Rockville Pike, Bethesda,
MD 20892. (301) 496-4000.
<>.
Office International des Epizooties. 12, rue de Prony, Paris,
France 75017. 33-(0)1 44 15 18 88; Fax: 33-(0)1 42 67 09
87. <>.
Patient Advocate Foundation. 700 Thimble Shoals Blvd,
Suite 200, Newport News, VA 23606. (757) 873-8999
or (800) 532-5274. <http://
www.patientadvocate.org>.
United States Food and Drug Administration. 5600 Fishers

Lane, Rockville, MD 20857. (888) 463-6332.
<>.
Maria Basile, PhD
Progressive locomotor ataxia see Tabes
dorsalis
Progressive sclerosing poliodystrophy see
Alpers’ disease
❙
Progressive multifocal
leukoencephalopathy
Definition
Progressive multifocal leukoencephalopathy is a rare,
fatal disease of the white matter of the brain that almost
solely strikes individuals who already have weakened im-
mune systems.
LetterP.qxd 10/1/04 11:08 AM Page 702
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
703
Progressive multifocal leukoencephalopathy
Key Terms
Immunocompromise A condition in which the
immune system is weak and ineffective.
Myelin An insulating layer of fats around nerve
fibers that allows nerve impulses to travel more
quickly.
Description
In progressive multifocal leukoencephalopathy,
myelin (the substance that wraps around nerve fibers, pro-
viding insulation and speeding nerve transmission) is pro-
gressively destroyed. Although the disease is caused by a

very prevalent virus (called JC virus), it only develops in
individuals who are immunocompromised (have weak-
ened immune systems).
Multiple areas of the brain are affected by the de-
myelination associated with progressive multifocal
leukoencephalopathy. Additionally, other abnormalities
and bizarre cells take up residence within the brain, caus-
ing destruction of normal brain tissue and impairing nor-
mal function.
Demographics
The causative virus in progressive multifocal leukoen-
cephalopathy, JC virus, is extremely common. It is thought
to be present in upwards of 85% of all children before the
age of nine, and probably is present in an even greater per-
centage of adults. However, the JC virus does not actually
cause any symptoms or disease, except in individuals who
have severely compromised immune systems. About
62.2% of all progressive multifocal leukoencephalopathy
cases occur in individuals with lymphatic cancers (lym-
phoproliferative disease, such as Hodgkin’s disease and
other lymphomas); 6.5% occur in individuals with cancer
of bone marrow cells (myeloproliferative disease or
leukemias); 2.2% occur in individuals with carcinomatous
disease (cancers that affect the lining of tissues or organs
of the body); and 10% occur in individuals with any of a
number of acquired immunodeficiency states (such as sys-
temic lupus erthematosus, sarcoidosis, and organ trans-
plant survivors). Among patients with Acquired
Immunodeficiency Syndrome (AIDS), about 10% of pa-
tients develop progressive multifocal leukoencephalopa-

thy. Only 5.6% of all cases of progressive multifocal
leukoencephalopathy occur in individuals with no other
underlying source of immunocompromise.
Causes and symptoms
Although much is left to be defined about the mech-
anism whereby progressive multifocal leukoencephalopa-
thy affects an individual, researchers believe that the JC
virus resides in the kidneys of most individuals. In normal,
nonimmunocompromised individuals, the virus stays
within the kidneys, doing no harm. In immunocompro-
mised individuals, the virus is reactivated, travels through
the circulatory system to the brain, and selectively de-
stroys myelinated nerve cells.
Patients with progressive multifocal leukoen-
cephalopathy experience a range of symptoms that grow
gradually worse over time, including headache and diffi-
culties with speech, thinking, walking, weakness, vision
problems (even blindness), memory problems, confusion,
slowness of movement, paralysis of half of the body, and
seizures. Eventually, patients lapse into a coma and die,
usually within just months of the onset of their initial
symptoms.
Diagnosis
Diagnosis is usually suggested by a patient’s charac-
teristic symptoms of progressive multifocal leukoen-
cephalopathy, in combination with evidence of white
matter destruction visualized on CT or MRI scanning of
the brain. Specialized tests on cerebrospinal fluid (called
polymerase chain reactions) may demonstrate the pres-
ence of JC virus DNA. However, only brain biopsy can re-

sult in an absolutely definitive diagnosis.
Treatment team
Patients with progressive multifocal leukoen-
cephalopathy are usually seen by neurologists, as well as
by hematologist/oncologists for patients with lymphoma
or leukemia, infectious disease specialists for patients with
AIDS, and a rheumatologist for individuals with specific
autoimmune disease.
Treatment
There are no treatments available to cure progressive
multifocal leukoencephalopathy. Some degree of slowing
of the relentless progression of the disease has been noted
in certain patients treated with the AIDS drug AZT.
Prognosis
Progressive multifocal leukoencephalopathy is uni-
formly fatal, usually within one to four months of the ini-
tial symptoms. A few patients have had brief remissions in
the disease progression, and have lived for several years
beyond diagnosis.
Resources
BOOKS
Berger, Joseph R., and Avindra Nath. “Progressive Multifocal
Leukoencephalopathy.” In Cecil Textbook of Internal
LetterP.qxd 10/1/04 11:08 AM Page 703
704
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
Progressive supranuclear palsy
Medicine, edited by Lee Goldman, et al. Philadelphia: W.
B. Saunders Company, 2000.
Roos, Karen L. “Viral Infections.” In Textbook of Clinical

Neurology, edited by Christopher G. Goetz. Philadelphia:
W. B. Saunders Company, 2003.
Tyler, Kenneth L. “Viral Meningitis and Encephalitis.” In
Harrison’s Principles of Internal Medicine, edited by
Eugene Braunwald, et al. NY: McGraw-Hill
Professional, 2001.
PERIODICALS
Pruitt, A. A. “Nervous System Infections in Patients with
Cancer.” Neurol Clin 21, no. 1 (February 1, 2003):
193–219
WEBSITES
National Institute of Neurological Disorders and Stroke
(NINDS). NINDS Progressive Multifocal
Leukoencephalopathy Information Page. May 29, 2002.
(June 4, 2004). < />health_and_medical/disorders/pml_doc.htm>.
Rosalyn Carson-DeWitt, MD
❙
Progressive supranuclear palsy
Definition
Progressive supranuclear palsy (PSP) is a rare degen-
erative disorder that causes serious and permanent deficits
in movement and cognitive function.
Description
Progressive supranuclear palsy is also known as
Steele-Richardson-Olszewski syndrome, reflecting the
names of persons who discovered the syndrome. PSP is a
neurodegenerative disease (symptoms worsen with time)
first described as a distinct disorder in 1964. Characteris-
tics of PSP include slow movement and stiffness, which are
also seen similarly in Parkinson’s Disease (PD). Persons

affected by PSP tend to have more postural imbalance with
falls than patients with PD. Additionally tremor is usually
absent in PSP patients, while those with PD have tremor.
PSP is an uncommon disorder and initially it may be diffi-
cult to clinically distinguish between PSP and PD. PSP
usually begins to produce symptoms in the sixth decade
(50–59 years of age) of life and the disorder progressively
worsens more quickly than PD. Patients with PSP typically
become disabled within five to ten years after diagnosis
(PD has a slower progression and typically persons can be-
come disabled 20 years after onset). PSP is the most com-
mon Parkinson-like or Parkinson-plus disease.
Demographics
The estimated prevalence (number of existing cases)
among persons older than 55 years is approximately
seven per 100,000 persons. Studies indicate that there
may be a slightly higher male prevalence (1.53), than fe-
male prevalence (1.23) per 100,000. In Perth, Australia,
the incidence (number of new cases) is estimated at three
to four per million cases. The incidence rate for ages 50-
99 is 5.3 per 100,000. The peak incidence (the peak age
range for new cases) is in the early sixties. PSP is not
thought to be genetically transmitted in families, but there
are some reported cases of inherited transmission. Survey
research (using a questionnaire) in 1996 revealed that pa-
tients with PSP were less likely than controls to have
completed 12 years of education, which suggests that ed-
ucation level is a marker for direct risk factors which can
include chemical exposure or nutritional problems. In
1999 a high prevalence of PSP was found in Guadeloupe

(French West Indies) which is related to ingestion of cer-
tain teas that are forms of custard apple (called “soursop”
and “sweetsop”).
Causes and symptoms
The cause of degeneration of nerve cells is unknown.
Patients affected with PSP have a gradual and progressive
damage to cells in the midbrain, which eventually leads to
atrophy (shrinkage and loss of normal cell architecture).
Patients have neuronal loss and neurofibrillary tangles in
the diencephalon, brain stem and basal ganglia. Several
theories have been proposed as potential causes. Initially,
the main causes of PSP was thought to be due to a virus
(possibly related to the influenza virus) or to a slow acting
toxin (i.e. “MPTP”, a drug of abuse contaminant, herbal
Caribbean teas, Cycad nut poisoning in Guam).
However, recent genetic research as of 1999 suggests
PSP may be a genetic disorder transmitted with autosomal
recessive transmission. The gene implicated with the con-
dition is called the tau gene. Analysis of the tau gene using
molecular biology techniques indicate that the tau gene in
PSP is different from genes observed in Alzheimer dis-
ease patients. Studies indicate that the tau gene in PSP is
similar to the gene in another disease (Cortico basal de-
generation). These genetic studies indicate that some nerve
cells may be partially controlled by genetic susceptibility
and also related to other environmental stressors/triggers
such as viruses and/or toxins.
The symptoms of PSP are insidious and typically
there is a prolonged phase of headaches, dizziness, fa-
tigue, arthralgias and depression. The most common

symptoms include postural instability and falls (seen in
63% of patients) and dyarthria (a symptom expressed in
35% of patients). Other important symptoms include
bradykinesia and visual disturbance (diplopia, burning
LetterP.qxd 10/1/04 11:08 AM Page 704
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
705
Progressive supranuclear palsy
Key Terms
Basl ganglia Brain structure at the base of the cere-
bral hemispheres involved in controlling movement.
Bradykinesia Extremely slow movement.
Brain stem The stalk of the brain which connects
the two cerebral hemispheres with the spinal cord.
It is involved in controlling vital functions, move-
ment, sensation, and nerves supplying the head and
neck.
Diencephalon A part of the brain that binds the
mesencephalon to the cerebral hemispheres, it in-
cludes the thalmus and the hypothalmus.
Diplopia A term used to describe double vision.
Dysarthria Slurred speech.
Neurofibrillary tangles Abnormal structures,
composed of twisted masses of protein fibers within
nerve cells, found in the brains of persons with
Alzheimer’s disease.
eyes, blurred vision and sensitivity to light) in 13% of af-
fected PSP patients. The front neck muscles or back neck
muscles may be affected. The rigidity of the spine is char-
acterized by a stiff extended spine. PSP patients also ex-

hibit eye movement paralysis. The eye lids may be held
wide open with eye movement paralysis resulting in a fa-
cial expression that can be described as “staring,” “aston-
ished,” or “puzzled.”
Eye movement difficulties usually begin with diffi-
culty looking up or down. There may be difficulty looking
right or left. These eye abnormalities may cause difficulty
during driving and reading. There is no treatment for eye
movement abnormalities. Patients with PSP do not have
eye muscle or eye nerve problems; the problem originates
in the brain stem area.
Diagnosis
Lab tests and neuroimaging can be performed to elim-
inate other possible causes. One specific high resolution
neuroimaging study called PET (positron emission to-
mography) scan can provide information about blood
flow and oxygen supply to the brain. PET scan analysis
has revealed a decrease in blood flow and oxygen metab-
olism in areas of the brain thought to degenerate in PSP pa-
tients (i.e. caudate, putamen and thalamus). Sleep patterns
in PSP affected patients are often abnormal and demon-
strated increased awakenings, diminished total sleep time,
and progressive loss of REM sleep. Patients can also de-
velop REM sleep behavior disorder consisting of abnormal
motor activity with vivid dreams during REM sleep.
Autopsy results after examination of brain tissue re-
veals neuronal loss and neurofibrillary tangles and gliosis
in the reticular formation and ocular (eye) motor nuclei, as
well as neuronal pathology in the midbrain. MRI neu-
roimaging studies can detect abnormal patterns in affected

areas within the brain.
Treatment team
As the disease progresses, specialists are required as
part of the treatment team. Consultation with rehabilita-
tion medicine specialist may help with walking stability
and safety. A speech therapist may modify diet if swal-
lowing is impaired. Consultation with an eye specialist
(ophthalmologist) may be indicated for the treatment of
eye problems.
Treatment
There is no effective therapy for PSP. Mediation gen-
erally has little or short term effects. Treatment is sup-
portive (palliative) until the person dies. Supportive
treatment can include speech therapy, walkers, antide-
pressants, artificial tears (to avoid drying of eyes from ex-
cess exposure) and caregiver support. Only few persons
demonstrate benefit with medication that increases the
neurotransmitters dopamine (dopaminergic) or acetyl-
choline (cholinergic drugs). A well balanced diet is rec-
ommended and gastrostomy (a surgical procedure to
redirect bowels to pass through an opening in the stomach)
is performed when feeding becomes problematic due to
dysphagia (difficulty swallowing), or risk of bronchoaspi-
ration (food lodging in the lungs due to abnormal swal-
lowing) is possible.
Recovery and rehabilitation
PSP is a chronic and progressive disorder which
means that symptoms worsen with the passing of time.
Close follow-up care is advisable, and during visits it is
necessary to provide family with direction and education.

If the patient opts for experimental treatment protocols, it
is mandatory to inform all concerned about potential side
effects. Physical therapy involvement can help to maxi-
mize safety at home and provide instruction in the use of
walking aids (i.e. wheelchair, walker).
Clinical trials
The National Institute of Neurological Disorders and
Stroke (NINDS) are currently sponsoring research con-
cerning diagnosis, treatment and causes of PSP. Addition-
ally, studies concerning Parkinson’s and Alzheimer’s
disease are being performed since a better understanding
of related diseases may provide valuable information con-
cerning PSP.
LetterP.qxd 10/1/04 11:08 AM Page 705
706
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
Progressive supranuclear palsy
Prognosis
In most patients the disease is fatal within six to 10
years. Complications of PSP are related to abnormal bal-
ance, immobility (a late feature of PSP) and decreased
cognition. Falls may cause patients to injure bones. Late
onset immobility can cause infectious complications
(pneumonia, urinary tract infection, or sepsis).
Special concerns
A well balanced diet is recommended and physical
therapy may help with walking problems and falls which
are the two major causes of disability. Educational con-
cerns are important and should be directed to the patient,
family members and caregivers. Education includes an un-

derstanding of the natural history of PSP and should in-
clude information concerning prognosis, complications,
supportive therapy. Patients and families may benefit from
PSP support group involvement.
Resources
BOOKS
Goetz, Christopher G., et al., eds. Textbook of Clinical
Neurology, 1st ed. Philadelphia: W. B. Saunders
Company, 1999.
Goldman, Lee, et al. Cecil’s Textbook of Medicine, 21st ed.
Philadelphia: W. B. Saunders Company, 2000.
PERIODICALS
Litvan, Irene. “Diagnosis and Mangement of Progressive
Supranuclear Palsy.” Seminars in Neurology 21 (2001).
WEBSITES
Hain, Timothy C. Progressive Supranuclear Palsy.
< />Progrssive Supranuclear Palsy. < />article.922569615.html>.
Progressive Supranuclear Palsy. <>.
Progressive Supranuclear Palsy Fact Sheet. <http://
www.ninds.nih.gov/health_and_medical/pubs/psp.htm>.
Progressive Supranuclear Palsy. <>.
ORGANIZATIONS
Society for Progressive Supranuclear Palsy, Woodholme
Medical Building. 1838 Greene Tree Road, #515,
Baltimore, MD 21208. (410) 486-3330 or
800-457-4777; Fax: (410) 486-4383.
<>.
The PSP Association, The Old Rectory, Wappenham,
Towcester, Northants NN12 8SQ, United Kingdom.
011-44-1327-860299; Fax: 011-44-1327-861007.

<>.
Laith Farid Gulli, MD
Nicole Mallory, MS, PA-C
❙
Pseudobulbar palsy
Definition
Pseudobulbar palsy refers to a group of symptoms—
including difficulty with chewing, swallowing, and
speech, as well as inappropriate emotional outbursts—that
accompany a variety of nervous system disorders.
Description
Pseudobulbar palsy refers to a cluster of symptoms
that can affect individuals suffering from a number of
nervous system conditions, such as amyotrophic lateral
sclerosis, Parkinson’s disease, stroke, multiple sclero-
sis, or brain damage due to overly rapid correction of low
blood sodium levels.
Causes and symptoms
Pseudobulbar palsy occurs when nervous system con-
ditions cause degeneration of certain motor nuclei (nerve
clusters responsible for movement) that exit the brain stem.
Patients with pseudobulbar palsy have progressive
difficulty with activities that require the use of muscles in
the head and neck that are controlled by particular cranial
nerves. The first noticeable symptom is often slurred
speech. Over time, speech, chewing, and swallowing be-
come progressively more difficult, eventually becoming
impossible. Sudden emotional outbursts, in which the pa-
tient spontaneously and without cause begins to laugh or
cry, are also a characteristic of pseudobulbar palsy.

Diagnosis
Diagnosis is usually made by noting the symptom
cluster characteristic of pseudobulbar palsy. Diagnostic
tests will be run to determine what underlying neurologi-
cal disorder has led to the development of pseudobulbar
palsy. In particular, neuroimaging (CT and MRI scans) can
be used to diagnose many of the conditions that prompt
the development of pseudobulbar palsy.
Treatment team
Neurologists usually care for patients with the kinds
of conditions that include the symptoms of pseudobulbar
palsy.
Treatment
There are no cures for pseudobulbar palsy; the symp-
toms usually progress over the course of several years,
leading to complete disability. Some medications may im-
prove the emotional symptoms associated with pseudob-
ulbar palsy; these include levodopa, amantadine,
amitriptyline, and fluoxetine.
LetterP.qxd 10/1/04 11:08 AM Page 706
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
707
Pseudotumor cerebri
Prognosis
The prognosis for pseudobulbar palsy is quite poor.
When the symptoms progress to disability, there is a high
risk of choking and aspiration (breathing food or liquids
into the lungs), which can lead to severe pneumonia and
death. The conditions with which pseudobulbar palsy is
associated also have a high risk of progression to death.

Resources
BOOKS
Friedman, Joseph. “Mood, Emotion, and Thought.” In
Textbook of Clinical Neurology, edited by Christopher G.
Goetz. Philadelphia: W. B. Saunders Company, 2003.
Murray, T. Jock, and William Pryse-Phillips. “Amyotrophic
Lateral Sclerosis.” In Noble: Textbook of Primary Care
Medicine, edited by John Noble, et al. St. Louis: W. B.
Saunders Company, 2001.
Rosalyn Carson-DeWitt, MD
❙
Pseudotumor cerebri
Definition
Pseudotumor cerebri is a chronic elevation of in-
tracranial pressure that causes papilloedema and possibly
blindness, which occurs in the absence of a mass lesion in
the brain.
Description
Pseudotumor cerebri primarily affects obese women
of childbearing age, and its cause is not known. The dis-
order is possibly the result of an abnormality in venous
blood outflow from the brain, or from an abnormality in
cerebrospinal fluid (CSF) flow. The increase in intracra-
nial pressure can result in headache, visual impairment,
pain, and hearing problems.
Demographics
Three significant studies concerning pseudotumor
cerebri have been conducted in Iowa and Louisiana, the
Mayo Clinic in Rochester, Minnesota, and Benghazi,
Libya. The incidence of pseudotumor cerebri increases in

women between 14 and 44 years of age, who are obese. In
the Iowa and Louisiana study, the incidence was 19.3 per
100,000 in women who were 20% over ideal weight. In the
Mayo Clinic study, the annual incidence number of new
cases between 1976 and 1990 was found to be approxi-
mately eight per 100,000 for obese women 15–44 years
old. In the Benghazi study (from 1982–1989), the annual
incidence was 21 per 100,000 obese women 15–44 years
old. No evidence of any racial or ethnic predilection exists.
Causes and symptoms
The cause of pseudotumor cerebri is unknown, but it
is thought to result from a faulty mechanism in CSF or ve-
nous flow from the brain. Certain risk factors have been
associated with the disorder that include female gender,
menstrual irregularity, obesity, recent weight gain, en-
docrine (hormone) disorders such as hypothyroidism (un-
deractive thyroid disorder), or medication taken such as
cimetidine (anti-ulcer), corticosteroids, lithium (used to
treat bipolar disorder), tetracycline, sulfa antibiotics, re-
combinant human growth hormone, oral contraceptives,
and vitamin A intake in infants.
Patients can have symptoms such as headache, ring-
ing sounds in the ears, double vision (diplopia), or pain in
the arms. Additionally, patients may have back pain, neck
pain, or stiffness and arthralgias in the shoulder, knee, and
wrist. Patients usually develop papilloedema, which can
causes visual obscurations (dimming), progressive loss of
peripheral vision, blurring, and sudden visual loss (result-
ing from intraocular hemorrhage).
Diagnosis

Neuroimaging studies are the best diagnostic tools,
especially brain magnetic resonance imaging (MRI)
scans. MRI scans provide good images that can reveal
other possible disease states that cause increased intracra-
nial pressure. General and special blood tests are typically
ordered. CSF studies are also indicated and are usually
done by inserting a needle into the lumbar region of the
spine to withdraw a fluid sample. CSF studies are done to
detect an infection within the central nervous system; the
sample is used for tumor tests.
Treatment team
Management of pseudotumor cerebri requires a lum-
bar puncture that is performed by a neurologist or
Key Terms
Cerebrospinal fluid A colorless and clear fluid
that contains glucose and proteins that bathe and
nourish the brain and spinal cord.
Recombinant human growth hormone A syn-
thetic form of growth hormone that can be given to
a patient to help skeletal growth.
Papilloedema Edema or swelling in the optic disk
(a portion of the optic nerve that collects nerves
from the light sensitive layer of the eye, also called
the retina).
Intraocular Inside the eye.
LetterP.qxd 10/1/04 11:08 AM Page 707
708
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
Pseudotumor cerebri
Retinal photograph showing the effects of a pseudotumor cerebri. (Phototake, Inc. All rights reserved.)

this is a surgical redirection of fluid flow in the brain,
which creates an outflow of fluid from the brain that de-
creases intracranial pressure.
Recovery and rehabilitation
A formal weight loss and exercise program is re-
quired once the diagnosis is established. Admission to the
hospital is uncommon, but some patients may be admitted
for a short stay for intravenous fluid hydration and pain
management in cases of intractable headache. Admission
to the hospital is also indicated if the patient is a surgical
candidate due to severe visual loss. Patients require edu-
cation concerning blindness and weight reduction. Pro-
grams designed to lose weight should include an exercise
program and psychological consultations. Many patients
do not successfully lose enough weight and may require
drastic treatment approaches such as gastric resection or
stapling.
internist. Visual problems may be monitored by a neuro-
ophthalmologist. Neurosurgical consultations are neces-
sary if treatment does not arrest or reverse the condition
quickly, within hours to days.
Treatment
Patients who do not develop visual loss are often
treated with a drug called acetazolamide (a carbonic an-
hydrase inhibitor) that lowers intracranial pressure. In per-
sons who present with more severe symptoms such as
early loss of vision, a short treatment course with high-
dose corticosteroids (prednisone) is recommended. Ta-
pering down from the initial corticosteroid dose is
individualized and based on the improvement of symp-

toms. If new visual loss is noted despite treatment, emer-
gency surgical intervention may be indicated. A procedure
called a lumboperitoneal shunt is the method of choice uti-
lized for prompt reduction of intracranial hypertension;
LetterP.qxd 10/1/04 11:08 AM Page 708
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
709
Pseudotumor cerebri
Clinical trials
The National Institute of Health is conducting a trial
concerning the role of thrombosis inside blood vessels and
the development of pseudotumor cerebri.
Prognosis
Typically, persons affected with pseudotumor cerebri
can develop blindness, which is the only severe and per-
manent complication of this disorder. The blindness,
which progressively worsens, is due to papilloedema.
Special concerns
Diligent treatment is required since eye deficits in
one or both eyes can have a very quick onset and can
be disabling. The disorder is not statistically corre-
lated with weight gain during pregnancy; however,
both pregnancy and pseudotumor cerebri are linked to
weight gain and female gender (within childbearing
age).
Resources
BOOKS
Marx, John A., et al (eds). Rosen’s Emergency Medicine:
Concepts and Clinical Practice, 5th ed. St. Louis: Mosby,
Inc., 2002.

Noble, John., et al (eds). Textbook of Primary Care Medicine,
3rd ed. St. Louis: Mosby, Inc., 2001.
WEBSITES
Health Topics A-Z. (May 23, 2004.) <>.
ORGANIZATIONS
Pseudotumor Cerebri Support Network. 8247 Riverside Drive,
Powell, OH 43065. (614) 895-8814. <udo
tumorcerebri.com>.
Laith Farid Gulli, MD
Robert Ramirez, DO
Nicole Mallory, MS, PA-C
Pyridostigmine see Cholinergic stimulants
LetterP.qxd 10/1/04 11:08 AM Page 709
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
711
R
❙
Radiation
Definition
Radiation and radioisotopes are extensively used
medications to allow physicians to image internal struc-
tures and processes in vivo (in the living body) with a min-
imum of invasion to the patient. Higher doses of radiation
are also used as means to kill cancerous cells.
Radiation is actually a term that includes a variety of
different physical phenomena. However, in essence, all
these phenomena can be divided into two classes: phe-
nomena connected with nuclear radioactive processes are
one class, the so-called radioactive radiation (RR); elec-
tromagnetic radiation (EMR) may be considered as the

second class.
Both classes of radiation are used in diagnoses and
treatment of neurological disorders.
Description
There are three kinds of radiation useful to medical
personnel: alpha, beta, and gamma radiation. Alpha radi-
ation is a flow of alpha particles, beta radiation is a flow
of electrons, and gamma radiation is electromagnetic ra-
diation.
Radioisotopes, containing unstable combinations of
protons and neutrons, are created by neutron activation.
This involves the capture of a neutron by the nucleus of an
atom, resulting in an excess of neutrons (neutron rich).
Proton-rich radioisotopes are manufactured in cyclotrons.
During radioactive decay, the nucleus of a radioisotope
seeks energetic stability by emitting particles (alpha, beta,
or positron) and photons (including gamma rays).
Radiation—produced by radioisotopes—allows ac-
curate imaging of internal organs and structures. Ra-
dioactive tracers are formed from the bonding of
short-lived radioisotopes with chemical compounds that,
when in the body, allow the targeting of specific body re-
gions or physiologic processes. Emitted gamma rays (pho-
tons) can be detected by gamma cameras and computer
enhancement of the resulting images and allows quick and
relatively noninvasive (compared to surgery) assessments
of trauma or physiological impairments.
Because the density of tissues is unequal, x rays (a
high frequency and energetic form of electromagnetic ra-
diation) pass through tissues in an unequal manner. The

beam passed through the body layer is recorded on special
film to produce an image of internal structures. However,
conventional x rays produce only a two-dimensional pic-
ture of the body structure under investigation.
Tomography (from the Greek tomos, meaning “to
slice”) is a method developed to allow the detailed con-
struction of images of the target object. Initially using the
x rays to scan layers of the area in question, with computer
assisted tomography a computer then analyzes data of all
layers to construct a 3D image of the object.
Computed tomography (also known as CT, CT scan)
and computerized axial tomography (CAT) scans use x
rays to produce images of anatomical structures.
Single proton (or photon) emission computed tomog-
raphy (SPECT) produces three-dimensional images of an
organ or body system. SPECT detects the presence and
course of a radioactive substance that is injected, ingested,
or inhaled. In neurology, a SPECT scan can allow physi-
cians to examine and observe the cerebral circulation.
SPECT produces images of the target region by detecting
the presence and location of a radioactive isotope. The
photon emissions of the radioactive compound containing
the isotope can be detected in a manner that is similar to
the detection of x rays in computed tomography (CT). At
the end of the SPECT scan, the stored information can be
integrated to produce a computer-generated composite
image.
Positron emission tomography (PET) scans utilize
isotopes produced in a cyclotron. Positron-emitting ra-
dionuclides are injected and allowed to accumulate in the

target tissue or organ. As the radionuclide decays, it emits
a positron that collides with nearby electrons to result in
the emission of two identifiable gamma photons. PET
LetterR.qxd 10/1/04 11:08 AM Page 711
712
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
Radiation
Key Terms
Radioisotopes An unstable isotope that emits ra-
diation when it decays or returns to a stable state.
Radiotherapy The use of x rays or other radioac-
tive substances to treat disease.
scans use rings of detectors that surround the patient to
track the movements and concentrations of radioactive
tracers. PET scans have attracted the interest of physicians
because of their potential use in research into metabolic
changes associated with mental diseases such as schizo-
phrenia and depression. PET scans are used in the diag-
nosis and characterizations of certain cancers and heart
disease, as well as clinical studies of the brain. PET uses
radio-labeled tracers, including deoxyglucose, which is
chemically similar to glucose and is used to assess meta-
bolic rate in tissues and to image tumors, and dopa, within
the brain.
Electromagnetic radiation
In contrast to imaging produced through the emission
and collection of nuclear radiation (e.g., x rays, CT scans),
magnetic resonance imaging (MRI) scanners rely on the
emission and detection of electromagnetic radiation.
Electromagnetic radiation results from oscillations of

components of electric and magnetic fields. In the simplest
cases, these oscillations occur with definite frequency (the
unit of frequency measurement is 1 Hertz (Hz), which is
one oscillation per second). Arising in some point (under
the action of the radiation source), electromagnetic radia-
tion travels with the velocity that is equal to the velocity
of the light, and this velocity is equal for all frequencies.
Another quantity, wavelength, is often used for the de-
scription of electromagnetic radiation (this quantity is sim-
ilar to the distance between two neighbor crests of waves
spreading on a water surface, which appear after dropping
a stone on the surface). Because the product of the wave-
length and frequency must equal the velocity of light, the
greater the wave frequency, the less its wavelength.
MRI scanners rely on the principles of atomic nu-
clear-spin resonance. Using strong magnetic fields and
radio waves, MRIs collect and correlate deflections
caused by atoms into images. MRIs allow physicians to
see internal structures with great detail and also allow ear-
lier and more accurate diagnosis of disorders.
MRI technology was developed from nuclear mag-
netic resonance (NMR) technology. Groups of nuclei
brought into resonance, that is, nuclei absorbing and emit-
ting photons of similar electromagnetic radiation such as
radio waves, make subtle yet distinguishable changes
when the resonance is forced to change by altering the en-
ergy of impacting photons. The speed and extent of the
resonance changes permit a non-destructive (because of
the use of low-energy photons) determination of anatom-
ical structures.

MRI images do not utilize potentially harmful ioniz-
ing radiation generated by three-dimensional x-ray CT
scans, but rely on the atomic properties (nuclear reso-
nance) of protons in tissues when they are scanned with
radio frequency radiation. The protons in the tissues, which
resonate at slightly different frequencies, produce a signal
that a computer uses to tell one tissue from another. MRI
provides detailed three-dimensional soft tissue images.
These methods are used successfully for brain inves-
tigations.
Radiation therapy (radiotherapy)
Radiotherapy requires the use of radioisotopes and
higher doses of radiation that are used diagnostically to
treat some cancers (including brain cancer) and other med-
ical conditions that require destruction of harmful cells.
Radiation therapy is delivered via external radiation
or via internal radiation therapy (the implantation/injection
of radioactive substances).
Cancer, tumors, and other rapidly dividing cells are
usually sensitive to damage by radiation. The goal of ra-
diation therapy is to deliver the minimally sufficient
dosage to kill cancerous cells or to keep them from divid-
ing. Cancer cells divide and grow at rates more rapid than
normal cells and so are particularly susceptible to radia-
tion. Accordingly, some cancerous growths can be re-
stricted or eliminated by radioisotope irradiation. The
most common forms of external radiation therapy use
gamma and x rays. During the last half of the twentieth
century, the radioisotope cobalt-60 was the frequently
used source of radiation used in such treatments. More

modern methods of irradiation include the production of x
rays from linear accelerators.
Iodine-131, phosphorus-32 are commonly used in ra-
diotherapy. More radical uses of radioisotopes include the
use of boron-10 to specifically attack tumor cells. Boron-
10 concentrates in tumor cells and is then subjected to neu-
tron beams that result in highly energetic alpha particles
that are lethal to the tumor tissue.
Precautions
Radiation therapy is not without risk to healthy tissue
and to persons on the health care team, and precautions
(shielding and limiting exposure) are taken to minimize
exposure to other areas of the patient’s body and to per-
sonnel on the treatment team.
LetterR.qxd 10/1/04 11:08 AM Page 712
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
713
Radiculopathy
Therapeutic radiologists, radiation oncologists, and a
number of technical specialists use radiation and other
methods to treat patients who have cancer or other tumors.
Care is taken in the selection of the appropriate ra-
dioactive isotope. Ideally, the radioactive compound loses
its radioactive potency rapidly (this is expressed as the half-
life of a compound). For example, gamma-emitting com-
pounds used in SPECT scans can have a half-life of just a
few hours. This is beneficial for the patients, as it limits the
contact time with the potentially damaging radioisotope.
The selection of radioisotopes for medical use is gov-
erned by several important considerations involving

dosage and half-life. Radioisotopes must be administered
in sufficient dosages so that emitted radiation is present in
sufficient quantity to be measured. Ideally the radioisotope
has a short enough half-life that, at the delivered dosage,
there is insignificant residual radiation following the de-
sired length of exposure.
New areas of radiation therapy that may prove more
effective in treating brain tumors (and other forms of can-
cers) include three-dimensional conformal radiation ther-
apy (a process where multiple beans are shaped to match
the contour of the tumor) and stereotactic radiosurgery
(used to irradiate certain brain tumors and obstructions of
the cerebral circulation). Gamma knives use focused
beams (with the patient often wearing a special helmet to
help focus the beams), while cyberknifes use hundreds of
precise pinpoint beams emanating from a source of irra-
diation that moves around the patient’s head.
Resources
BOOKS
Saha, Gopal B. Fundamentals of Nuclear Pharmacy. New
York: Springer-Verlag, 1999.
WEBSITES
Society of Nuclear Medicine. “What Is Nuclear Medicine?”
May 12, 2004 (May 27, 2004). <http://
www.snm.org/nuclear/index.html>.
Alexander Ioffe
❙
Radiculopathy
Definition
Radiculopathy refers to disease of the spinal nerve

roots (from the Latin radix for root). Radiculopathy pro-
duces pain, numbness, or weakness radiating from the
spine.
Description
At the joints between the vertebrae, sensory nerves
(nerves conducting sensory information toward the cen-
tral nervous system) and motor nerves (nerves conduct-
ing commands to muscles away from the central nervous
system) connect to the spinal cord. Each spinal nerve di-
vides or fans out just before merging with the spinal cord.
These smaller, separate nerve bundles are termed the roots
of the nerve because they are reminiscent of the way the
roots of a plant divide in the ground.
Damage to the spinal nerve roots can lead to pain,
numbness, weakness, and paresthesia (abnormal sensa-
tions in the absence of stimuli) in the limbs or trunk. Pain
may be felt in a region corresponding to a dermatome, an
area of skin innervated by the sensory fibers of a given
spinal nerve or a dynatome, an area in which pain is felt
when a given spinal nerve is irritated. Dynatomes and der-
matomes may overlap, but do not necessarily coincide.
Radiculopathies are categorized according to which
part of the spinal cord is affected. Thus, there are cervical
(neck), thoracic (middle back), and lumbar (lower back)
radiculopathies. Lumbar radiculopathy is also known a
sciatica. Radiculopathies may be further categorized by
what vertebrae they are associated with. For example,
radiculopathy of the nerve roots at the level of the seventh
cervical vertebra is termed C7 radiculopathy; at the level
of the fifth cervical vertebra, C5 radiculopathy; at the level

of the first thoracic vertebra, T1 radiculopathy; and so on.
Radiculopathy is to be distinguished from myelopa-
thy, which involves pathological changes in or functional
problems with the spinal cord itself rather than the nerve
roots. Sometimes, radiculopathy is also distinguished from
radiculitis, the latter being defined as irritation (hence the
“itis” suffix) of a nerve root that causes pain in the der-
matome or dynatome corresponding to that nerve. Radicu-
lopathy, on the other hand, denotes spinal nerve
dysfunction (not just irritation) presenting with pain, al-
tered reflex, weakness, and nerve-conduction abnormali-
ties. Pain may not be present with radiculopathy, but is
always present with radiculitis.
Demographics
Millions of persons experience some form of radicu-
lopathy at some point in their lives. Because many of the
causes of radiculopathy are long-term diseases (e.g., anky-
losing spondylosis, diabetes) or diseases that tend to affect
the elderly (e.g., arthritis), radiculopathy occurs more
often in the middle-aged and elderly than in the young.
However, injuries due to sports, heavy lifting, or bad pos-
ture affect the young as well. Cervical disc herniation
with radiculopathy (mostly involving the C4 to C5 levels)
affects 5.5 per 100,000 adults every year, with the highest
risk being for adults 35 to 55 years year old.
LetterR.qxd 10/1/04 11:08 AM Page 713
714
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
Radiculopathy
Key Terms

Dermatome An area of skin that receive sensa-
tions through a single nerve root.
Dynatome An area in which pain is felt when a
given spinal nerve is irritated.
Motor nerves Nerves conducting commands to
muscles away from the central nervous system.
Sensory nerves Nerves conducting sensory infor-
mation toward the central nervous system.
Causes and symptoms
Radiculopathy can be caused by any disease or injury
process that compresses or otherwise injures the spinal
nerve roots. Violent blows or falls, cancer, some infections
such as flu and Lyme disease, diseases that lead to de-
generation of the vertebrae and/or intervertrebral discs (os-
teoarthritis), slipped or herniated discs, scoliosis, and other
factors can cause radiculopathy. For example, extreme
backward bending of the neck can trigger cervical radicu-
lopathy. This has given rise to a recently-recognized cate-
gory of radiculopathy termed “salon sink radiculopathy,”
so-called because salon patrons are asked to tip their heads
sharply backward into sinks for shampooing. Spondylosis
(immobilization and growing-together of one or more ver-
tebral joints, often due to osteoarthritis) can deform the
structures of bone, cartilage, and ligament through which
spinal nerves must pass, leading to cervical and lumbar
radiculopathy. Thoracic and lumbar radiculopathies are a
common result of diabetes, which can impair blood flow
to the spinal nerve roots.
Diagnosis
Radiculopathy is a possible diagnosis when numb-

ness, pain, weakness, or paresthesia of the extremities or
torso are reported by a patient, especially in a dermatomal
pattern. However, these symptoms can also be caused by
nerve compression remote from the spine, and the physi-
cian must rule out this possibility before ruling in favor of
radiculopathy. Electrodiagnostic studies can help distin-
guish radiculopathy from other diagnoses. These tech-
niques include current perception threshold testing, which
tests patient ability to sense alternating electric currents at
several frequencies; electromyographic nerve conduction
tests; and testing of sensory evoked potentials (changes in
brain waves in response to sensory stimuli).
When radiculopathy is diagnosed, the location of the
affected nerve roots and, ultimately, the cause of their
dysfunction must be determined. Diagnosticians look at
the precise features of radicular symptoms in order to de-
termine the spinal level of the affected root or roots. For
example, radiculopathy at the C7 level (the nerve root
most often affected by herniated cervical disc) is charac-
terized by weak triceps and wrist extensor muscles and a
numb middle finger. Radiculopathy at the L3 (third lum-
bar disc) level is characterized by decreased patellar
(kneecap) reflex, loss of sensation and/or pain in the an-
terior (forward) part of the thigh, and weakness in quadri-
ceps muscle; and so on.
X ray or MRI may be used to confirm the diagnosis.
A herniated disc, for example, will be revealed by imag-
ing. A herniated disc is one that has partly popped or
bulged out from between the vertebra above and below it.
This may place pressure on the nerve roots and on the

spinal cord itself.
In persons with spinal cancer or other progressive dis-
orders, the appearance of radiculopathy may be an impor-
tant sign that pressure is beginning to be exerted by the
tumor or some other changing structure. This may signal
that it is time for surgical intervention.
Treatment team
Diagnosis of radiculopathy will usually involve a
neurologist. An orthopedist will usually be involved as
well. Other specialists will be required depending on the
cause of the radiculopathy (e.g., oncologist, if cancer is
present). Treatment will usually call for a physical thera-
pist. An orthopedic surgeon would perform any necessary
surgery.
Treatment
Treatment for radiculopathy varies with the nature
and severity of the disease process or injury that has
caused the disorder. Conservative (non-surgical) treatment
is often attempted first. This consists primarily of rest,
exercise, and medication. Patient-specific exercises are
prescribed by a physical therapist for the targeted strength-
ening of muscles and other supporting tissues to relieve
pressure on affected spinal nerve roots. Weight loss may
be advised to decrease stress on the spine. Medications
may include oral opioids (e.g., morphine) or other anal-
gesic (anti-pain) medications. In severe cases, injection of
an opioid by an external or implanted pump directly into
the affected area may be prescribed. Epidural corticos-
teroid injections, selective nerve root block, and epidural
lysis (destruction) of adhesions are also used to treat

radiculopathy. A soft neck collar may be prescribed for
persons with cervical radiculopathy.
When conservative treatment fails, surgery may be
necessary. The primary purpose of surgery is to take pres-
sure off of affected nerve roots or the blood vessels that
serve them and to stabilize spinal structure, but surgery
LetterR.qxd 10/1/04 11:08 AM Page 714
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
715
Ramsay-Hunt syndrome type II
may also sever nerves in order to relieve severe pain. Fu-
sion of vertebrae (i.e., removal of the flexible interverte-
bral disc and joining of the adjacent vertebrae so that they
grow into a single bone) was for many decades a common
treatment for intractable radiculopathy, but as of 2003, a
novel implant, the Bryan disc, was under study by the US
Food and Drug Administration. The Bryan disc is a flexi-
ble disc or ring of titanium and Teflon that is used to re-
place the intervertebral disc in patients with degenerative
disc disease. Two versions of the disc, one cervical (for the
neck) and the other lumbar (for the lower back) were under
development. Early reports from surgeons were positive.
The advantage of such an implant over fusion is that the
patient does not lose flexibility in that part of their spine.
Recovery and rehabilitation
Exercise is key to the treatment of both conservative
and surgical treatment of radiculopathy. It may even be
curative in some cases. It is also an important aspect of re-
covery from surgery. Exercise is done as directed by a
physical therapist.

Clinical trials
As of mid-2004, a clinical trial sponsored by the Na-
tional Institute of Dental and Craniofacial Research was
recruiting participants. The goal of this clinical trial was to
evaluate the effectiveness of two drugs (i.e., nortriptyline
and MS Contin, a type of morphine) in treating lumbar
radiculopathy, also known as sciatica. This was a phase II
clinical trial, meaning that it involved a medium-size
group (100–300 participants) to evaluate effectiveness and
side effects of the treatment. Persons interested in partic-
ipating should contact the Patient Recruitment and Public
Liaison Office at telephone (800) 411-1222, or e-mail at:

Prognosis
Prognosis varies with the underlying process causing
the radiculopathy. For sports injuries, at one extreme, the
prognosis is excellent; for degenerative disc disorders,
even surgery may not completely or permanently resolve
the problem. However, new surgical techniques are im-
proving this picture.
Resources
PERIODICALS
Kilcline, Bradford A. “Acute Low Back Pain: Guidelines for
Treating Common and Uncommon Syndromes.”
Consultant (October 1, 2002).
Lauerman, William C. “When Back Surgery Fails: What’s the
Next Step?” Journal of Musculoskeletal Medicine (June
1, 1999).
Lenrow, David A. “Chronic Neck Pain: Mapping Out
Diagnosis and Management; Part 1: Step-by-step

Algorithms Can Show the Way to Effective Treatment.”
Journal of Musculoskeletal Medicine (June 1, 2002).
“Neck Problems Tied to Salon Sinks.” Daily News (Los
Angeles) (October 6, 1999).
OTHER
“Cervical Radiculopathy.” Neuroland. />spine/c_radi.htm (April 29, 2004).
Skelton, Alta, “Lumbar radiculopathy.” <ne
universe.com/displayarticle.php/article1469.html>
(April 29, 2004).
ORGANIZATIONS
National Institute for Neurological Diseases and Stroke
(NINDS). 6001 Executive Boulevard, Bethesda, MD
20892. (301) 496-5751 or (800) 352-9424.
<>.
Larry Gilman, PhD
❙
Ramsay-Hunt syndrome
type II
Definition
Ramsay-Hunt syndrome type II is a very rare, pro-
gressive neurological disorder that causes epilepsy,
tremor, mental impairment, and eventually death.
Description
Ramsay-Hunt syndrome type II begins in adulthood.
It is a relentlessly progressive degenerative disease that
culminates in death, characterized by Parkinson-like
tremors, and muscle jerks (myoclonus).
Demographics
The average age of onset is about 30 years of age.
Causes and symptoms

Some cases seem to be caused by abnormalities of the
mitochondria within the cell. Mitochondria are the cells’
power stations. They are organelles within each cell that
are responsible for producing energy.
Some cases of Ramsay-Hunt syndrome type II appear
to be inherited in an autosomal dominant fashion, mean-
ing that a child who has one parent with the abnormal gene
has a 50:50 chance of inheriting the disorder. Other cases
appear to be inherited in an autosomal recessive fashion,
meaning that individuals who develop the disease have in-
herited defective genes from both parents.
LetterR.qxd 10/1/04 11:08 AM Page 715
716
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
Rasmussen’s encephalitis
Key Terms
Mitochondria The organelles within each cell that
are responsible for the production of energy.
Myoclonus Involuntary jerking or twitching of
muscles.
Ramsay-Hunt syndrome type II begins as an intention
tremor in the limbs, particularly the arms. An intention
tremor is an involuntary shaking or trembling that occurs
when an individual is attempting a purposeful movement;
the tremor is not manifested when the individual is at rest.
The intention tremor generally occurs in just one limb.
Over time, the entire muscular system is affected. In ad-
dition to the tremor, individuals with Ramsay-Hunt syn-
drome type II experience sudden twitching or contraction
of muscle groups, called myoclonus. Some individuals ex-

perience progressive hearing impairment. As the disease
progresses, the individual experiences decreased muscle
tone, increasing weakness, disturbances of fine motor con-
trol, difficulty walking, epilepsy, and (in some cases) men-
tal deterioration. The disease usually progresses over the
course of about 10 years, ultimately resulting in the death
of the patient.
Diagnosis
An electroencephalogram (EEG) may reveal certain
abnormalities of the electrical patterns in the brain. Mus-
cle biopsy may or may not reveal mitochondrial abnor-
malities.
Treatment team
Ramsay-Hunt syndrome type II is usually diagnosed
and treated by a neurologist. In an effort to maintain func-
tioning as long as possible, other treatment members may
include physical therapists, occupational therapists, and
speech and language therapists.
Treatment
There is no cure for Ramsay-Hunt syndrome type II.
Seizures may respond to antiseizure medications such as
phenobarbital, clonazepam, or valproic acid. The invol-
untary muscle jerking (myoclonus) may decrease with
such medication as valproic acid; benzodiazepines such
as clonazepam; L-tryptophan; 5-hydroxytryptophan with
carbidopa; or piracetam.
Prognosis
Ramsay-Hunt syndrome type II generally progresses
to death within about 10 years of the onset of symptoms.
Resources

BOOKS
Foldvary-Schaefer, Nancy, and Elaine Wyllie. “Epilepsy.” In
Textbook of Clinical Neurology, edited by Christopher G.
Goetz. Philadelphia: W.B. Saunders Company, 2003.
PERIODICALS
Sacquegna, T. “Normal Muscle Mitochondrial Function in
Ramsay-Hunt Syndrome.” Italian Journal of Neurological
Science 10 (1) (1 February 1989): 73–75.
Tassinari, C. A. “Dyssenergia Cerebellaris Myoclonica
(Ramsay-Hunt Syndrome): A Condition Unrelated to
Mitochondrial Encephalomyopathies.” Journal of
Neurology, Neurosurgery, and Psychiatry 52 (2) (1
February 1989): 262–265.
WEBSITES
National Institute of Neurological Disorders and Stroke
(NINDS). Ramsay-Hunt Syndrome Type II Fact Sheet.
(May 23, 2004.) < />health_and_medical/disorders/ramsey2.htm>.
ORGANIZATIONS
National Ataxia Foundation. 2600 Fernbrook Lane, Suite 119,
Minneapolis, MN 55447-4752. (763) 553-0020; Fax:
(763) 553-0167. <>.
WE MOVE. 204 West 84th Street, New York, NY 10024. (212)
875-8389 or (800) 437-MOV2.
<>.
Rosalyn Carson-DeWitt, MD
❙
Rasmussen’s encephalitis
Definition
Rasmussen’s encephalitis, also termed Rasmussen’s
syndrome, is a rare degenerative brain disease that initially

affects only one side of the brain. It first manifests in child-
hood with the onset of epileptic seizures. Later, it pro-
gresses to paralysis of one side of the body (hemiparesis),
blindness in one eye (hemianopsia), and loss of mental
function. The seizures in Rasmussen’s encephalitis usually
resist therapy with anticonvulsant drugs, but respond well
to hemispherectomy, the surgical removal of the entire af-
fected side of the brain.
Description
Rasmussen’s encephalitis usually appears in children,
but may also strike in adulthood. It initially affects only
one side (hemisphere) of the brain. The disease causes un-
controllable seizures and other symptoms that become
progressively worse. The affected hemisphere shows
changes characteristic of chronic inflammation, including
long-term atrophy or shrinkage, hence, the term en-
cephalitis (inflammation of the brain). Unless the affected
LetterR.qxd 10/1/04 11:08 AM Page 716
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
717
Rasmussen’s encephalitis
Key Terms
Aphasia Total or partial loss of the ability to use or
understand language; usually caused by stroke,
brain disease, or injury.
Autoimmune disorder Disorders in which the
body mounts a destructive immune response
against its own tissues.
Blood-brain barrier The protective membrane
that separates circulating blood from brain cells, al-

lowing some substances to enter while others, such
as certain drugs, are prevented from entering brain
tissue.
Cytomegalovirus A herpes type of virus that may
be transmitted through blood or body fluids and
can be fatal in people with weakened immune sys-
tems.
Encephalitis Inflammation of the brain.
Hemiparesis Muscle weakness on one side of the
body.
Neurotransmitter A chemical that is released dur-
ing a nerve impulse that transmits information from
one nerve cell to another.
hemisphere is removed, the disorder eventually spreads to
the brain’s other hemisphere.
Demographics
Rasmussen’s encephalitis is very rare; between 1958,
when the syndrome was first identified, and 2000, barely
100 cases were identified. The medical literature does not
describe a higher incidence of this disease in either gender
or in any particular racial group or geographical area.
Causes and symptoms
For many years, the cause of Rasmussen’s encephali-
tis was a mystery. It seemed to resemble a viral infection,
but despite much research, no organism could be consis-
tently found in the brains of those who had suffered from
the disorder. Finally, in the early 1990s, it was discovered
that Rasmussen’s encephalitis is an autoimmune disease,
that is, a disorder in which the body is attacked by its own
immune system.

Specifically, the body responds to one of the gluta-
mate receptors, GluR3, as if it were an invading organism.
Glutamate is a neurotransmitter, or one of the chemicals
that neurons use to signal to each other. A receptor is a
complex molecule embedded in the cell membrane of a
neuron that detects the presence of a specific neurotrans-
mitter and responds by causing some change in the neuron
itself, such as admitting a flow of sodium, potassium, or
calcium ions into the cell. There are at least 20 distinct re-
ceptors for glutamate in the brain, one of which is denoted
GluR3. In Rasmussen’s encephalitis, the body (for reasons
still unknown) produces anti-GluR3 antibodies. Attracted
by these antibodies, groupings of special immune system
proteins, termed complement, gather on neurons in the af-
fected parts of the brain, eventually forming “membrane
attack complexes” that damage the neurons. It is not
known why this autoimmune response attacks only one
side of the brain at first, but it was hypothesized that a
breach in the blood-brain barrier in one part of the brain
might allow initial access of antibodies to neurons. The ar-
rival of lymphocytes in the affected area, with consequent
swelling of tissues, may then cause further damage to the
blood-brain barrier and allow more anti-GluR3 antibodies
access to the neurons. Finally, it remains possible that in-
fection by cytomegalovirus may play a role in triggering
the autoimmune processes of Rasmussen’s encephalitis.
Cytomegalovirus DNA has been detected in the brains of
some patients.
The first symptom of Rasmussen’s encephalitis is
seizures, usually beginning suddenly before the age of 10.

Loss of control over voluntary movements, loss of speech
ability (aphasia), hemiparesis (weakness on one side of
the body), dementia, mental retardation, and eventually,
death, will follow if untreated.
Diagnosis
Rasmussen’s encephalitis is diagnosed by the sudden
onset of epileptic seizures in childhood, gradual worsen-
ing of seizures, gradual intellectual deterioration, the onset
of hemiparesis and other one-sided symptoms, and the
elimination of other possible causes for these symptoms.
Treatment
Early in the progress of Rasmussen’s encephalitis, an-
ticonvulsant drugs may help control seizures. Use of the
anti-cytomegalovirus drug ganciclovir early in the syn-
drome produces improvement in some patients. Also,
some patients have shown dramatic positive response to
removal of anti-GluR3 antibodies from the blood by a
process known as plasmapheresis. Currently, researchers
are studying the hypothesis that drugs to prevent the for-
mation of membrane-attack complexes might slow or halt
the progression of Rasmussen’s encephalitis as well as of
other neurodegenerative diseases. However, the treatment
of choice remained hemispherectomy, surgical removal of
the affected half of the brain.
Remarkably, children may show little or no change in
personality and no loss of intelligence or memory after
having half their brain removed. Some children are irrita-
ble, withdrawn, or depressed immediately after surgery,
LetterR.qxd 10/1/04 11:08 AM Page 717
718

GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
Reflex sympathetic dystrophy
but these symptoms are not permanent. So flexible is brain
development that a child with a hemispherectomy may be-
come fluent in one or more languages even if the left side
of the brain, where the speech centers are usually located,
is removed. Blindness or vision loss in one eye usually re-
sults from hemispherectomy, but normal hearing in both
ears may be recovered. The older the patient is when the
surgery is performed, however, the more likely they are to
suffer permanent sensory, speech, and motor losses.
Recovery and rehabilitation
Rehabilitation begins immediately after hemi-
spherectomy with passive range-of-motion exercises.
Physical, occupational, and speech therapists are required.
For children of school age, neuropsychological testing
can help determine what academic setting or grade level is
best. Children with hemispherectomies are often able to
participate in school at the level appropriate for their age.
Prognosis
The prognosis for children below the age of 10 who
are treated early in the course of the syndrome is good.
This group can often achieve normal psychosocial and in-
tellectual functioning. Without hemispherectomy, however,
persons with Rasmussen’s encephalitis eventually suffer
near-continuous seizures, mental retardation, and death.
Resources
BOOKS
Graham, David I., and Peter L. Lantos. Greenfield’s
Neuropathology, 6th edition. Bath, UK: Arnold, 1997.

PERIODICALS
Cleaver, Hannah. “Girl Left with Half a Brain Is Fluent in Two
Languages.” Daily Telegraph (London, England), May
23, 2002.
Duke University. “Mild Injury May Render Brain Cells
Vulnerable to Immune System Attack.” Ascribe Higher
Education News Service October 23, 2002.
Lilly, Donna J. “Functional Hemispherectomy: Radical
Treatment for Rasmussen’s Encephalitis.” Journal of
Neuroscience Nursing April 1, 2000.
Mercadante, Marcos T. “Genetics of Childhood Disorders:
XXX. Autoimmune Disorders, Part 3: Myasthenia Gravis
and Rasmussen’s Encephalitis.” Journal of the American
Academy of Child and Adolescent Psychiatry (September
1, 2001).
Zuckerberg, Aaron. “Why Would You Remove Half a Brain?
The Outcome of 58 Children after Hemispherectomy–The
Johns Hopkins Experience: 1968–1996.” Pediatrics
(August 1, 1997).
OTHER
“NINDS Rasmussen’s Encephalitis Information Page.” National
Institute of Neurological Disorders and Stroke. March 30,
2004 (June 2, 2004). < />health_and_medical/disorders/rasmussn_doc.htm>.
ORGANIZATIONS
National Organization for Rare Disorders (NORD). P.O. Box
1968 (55 Kenosia Avenue), Danbury, CT 06813-1968.
(203) 744-0100 or (800) 999-NORD; Fax: (203) 798-
2291. <e
diseases.org>.
Larry Gilman, PhD

❙
Reflex sympathetic dystrophy
Definition
Reflex sympathetic dystrophy is the feeling of pain
associated with evidence of minor nerve injury.
Description
Historically reflex sympathetic dystrophy (RSD)
was noticed during the Civil War in patients who suffered
pain following gunshot wounds that affected the median
nerve (a major nerve in the arm). In 1867 the condition
was called causalgia from the Greek term meaning “burn-
ing pain.” Causalgia refers to pain associated with major
nerve injury. The exact causes of RSD are still unclear. Pa-
tients usually develop a triad of phases. In the first phase,
pain and sympathetic activity is increased. Patients will
typically present with swelling (edema), stiffness, pain,
increased vascularity (increasing warmth), hyperhydrosis,
and x-ray changes demonstrating loss of minerals in bone
(demineralization). The second phase develops three to
nine months later, It is characterized by increased stiffness
and changes in the extremity that include a decrease in
warmth and atrophy of the skin and muscles. The late
phase commencing several months to years later presents
with a pale, cold, painful, and atrophic extremity. Patients
at this stage will also have osteoporosis.
It has been thought that each phase relates to a spe-
cific nerve defect that involves nerve tracts from the pe-
riphery spinal cord to the brain. Both sexes are affected,
but the number of new cases is higher in women, adoles-
cents, and young adults. RDS has been associated with

other terms such as Sudeck’s atrophy, post-traumatic os-
teoporosis, causalgia, shoulder-hand syndrome, and reflex
neuromuscular dystrophy.
Causes and symptoms
The exact causes of RSD at present is not clearly un-
derstood. There are several theories such as sympathetic
overflow (overactivity), abnormal circuitry in nerve im-
pulses through the sympathetic system, and as a post-op-
erative complication for both elective and traumatic
LetterR.qxd 10/1/04 11:08 AM Page 718
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
719
Refsum disease
Key Terms
Atrophy Abnormal changes in a cell that lead to
loss of cell structure and function.
Osteoporosis Reduction in the quantity of bone.
surgical procedures. Patients typically develop pain,
swelling, temperature, color changes, and skin and muscle
wasting.
Diagnosis
The diagnosis is simple and confirmed by a local
anesthetic block along sympathetic nerve paths in the hand
or foot, depending on whether an arm or leg is affected. A
test called the erythrocyte sedimentation rate (ESR) can
be performed to rule out diseases with similar presentation
and arising from other causes.
Treatment
The preferred method to treat RSD includes sympa-
thetic block and physical therapy. Pain is improved in mo-

tion of the affected limb improves. Patients may also
require tranquilizers and mild analgesics. Patients who re-
ceived repeated blocks should consider surgical symath-
ectomy (removal of the nerves causing pain).
Prognosis
The prognosis for treatment during phase one is fa-
vorable. As the disease progresses undetected into phase
two or three the prognosis for recovery is poor.
Resources
BOOKS
Canale, S., et al. Campbell’s Operative Orthopaedics, 9th ed.
Mosby, Inc., 1998.
Goetz, Christopher G., et al., eds. Textbook of Clinical
Neurology, 1st ed. W. B. Saunders Company, 1999.
Rockwood, Charles A., David P. Green, et al. Fractures in
Adults, 4th ed. Lippincott-Raven Publishers, 1996.
Ruddy, Shaun, et al., eds. Kelly’s Textbook of Rheumatology,
6th ed. W. B. Saunders Company, 2001.
OTHER
Reflex Sympathetic Dystrophy Syndrome Association of
America. < />Laith Farid Gulli, MD
Robert Ramirez, BS
❙
Refsum disease
Definition
Refsum disease is one of several inherited disorders
that are collectively called leukodystrophies. Refsum dis-
ease results from defects in the formation of the myelin
sheath, a fat covering that protects the nerves in the brain
and spinal cord.

Description
Refsum disease has also been called Refsum-
Thiébaut disease and Refsum-Thiébaut-Klenk-Kahlke
disease since Drs. W. Kahlke, E. Klenk, M.F. Thiébaut,
and Sigvald Bernhard Refsum all contributed to the iden-
tification and clinical characterization of the disorder. The
Norwegian neurologist, Sigvald Refsum first described
the disorder in 1946.
Refsum disease is a rare genetic disorder that affects
the ability of the body to breakdown fats, a process called
fatty acid oxidation. As a result, a metabolite called phy-
tanic acid accumulates in the blood as well as other tissues.
Phytanic acid is not produced by the human body but is
obtained from meat, dairy, and fish products. Phytanic acid
is a branched chain fatty acid. The accumulation of this
compound in the blood was detected by the German sci-
entist Klenk and Kahlke around 1963. Phytanic acid can
also be produced through the breakdown of a substance
that is found in green leafy vegetables called phytol.
Refsum disease is inherited as an autosomal recessive
disorder, which means that two unaffected carrier parents
have a 25% chance of having an affected child in every
pregnancy. Other less commonly used synonyms for Ref-
sum syndrome include: ataxia hereditaria hemeralopia
polyneuritiformis, hemeralopia heredotaxia polyneuriti-
formis, hereditary motor sensory neuropathy type IV,
heredopathia atactica poluneuritiformis, and phytanic acid
storage syndrome.
Demographics
Refsum disease is an extremely rare disorder that af-

fects males and females with equal frequency. It has been
observed in Norwegian populations as well as others.
Causes and symptoms
One of the earliest symptoms in Refsum disease that
the patients develop is night blindness. The age of onset of
all clinical manifestations tends to occur during childhood
and usually develop before 50 years of age. It is a pro-
gressive disorder characterized by periods of subtle wors-
ening and often appears to be in remission.
LetterR.qxd 10/1/04 11:08 AM Page 719
720
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
Refsum disease
12
13
14
15
11
11
1
p
q
22
26
25
21
23
24
1
2

Chromosome 10
OAT: Gyrate atrophy
Apert syndrome
Crouzon syndrome
PAHX: Refsum disease
Refsum disease, on chromosome 10. (Gale Group.)
Key Terms
Autosomal recessive disorder A genetic disorder
that is inherited from parents that are both carriers,
but do not have the disorder. Parents with an af-
fected recessive gene have a 25% chance of pass-
ing on the disorder to their offspring with each
pregnancy.
Leukodystrophy A genetically determined pro-
gressive disorder that affects the brain, spinal cord,
and peripheral nerves.
Myelin A fat-like substance that forms a protective
sheath around nerve fibers.
People with Refsum disease typically experience pro-
gressive hearing loss due to nerve damage that occurs
early during development. They can develop a progressive
degeneration of the eye leading to blindness due to an
atypical form of retinitis pigmentosa, a degenerative con-
dition associated with night blindness and pigment
changes in the retina. The visual loss involves progressive
constriction of the visual fields and these patients can de-
velop nystagmus (an involuntary oscillation of the eyeball)
as well as cataracts.
Cerebellar ataxia (brain-damage-related loss of motor
coordination) can also occur with Refsum disease, leading

to an unsteady gait. They can have syndactyly of the fin-
gers, where two fingers appear fused due to a failure to
separate during embryo formation. The neurological
damage appears to be localized toward the head and trunk
of the body (rather than the limbs). A fetus with Refsum
disease often develops heart disease and can also be born
with skeletal abnormalities in bone formation. It is also
common for people with Refsum disease to lose their
sense of smell. Finally, changes in the skin can also occur
with Refsum disease.
Refsum was the first genetic disorder identified to be
caused by defects in lipid (fat) metabolism. It is currently
felt to be caused by mutations in a gene (PAHX) that en-
codes a protein called phyanoly-CoA hydroxylase and is
important for metabolizing phytanic acid.
Diagnosis
The diagnosis for Refsum disease is made based on
the development of clinical manifestations and biochem-
ical analysis detecting elevated phytanic acid in the blood.
Treatment team
There are several specialists that are helpful in the di-
agnosis, treatment, and long-term care of patients with Ref-
sum disease.A neurologist is helpful initially in diagnosing
the disorder, as well as providing the appropriate follow-up
studies and treatment regimen. A genetic counselor is help-
ful in explaining the recurrence risks to the family, espe-
cially if they are considering reproductive implications.
Treatment
Dietary treatment involving the restriction of foods
that contain phytanic acid began in Norway in 1966 by

Professor Lorentz Eldjarn, the Head of the Central Labo-
ratory and Institute for Clinical Biochemistry at the Oslo
University Hospital, Rikshospitalet. This treatment con-
tinues today. Additionally, plasmapheresis or the removing
of plasma from the patient’s blood may also be helpful and
necessary.
Recovery and rehabilitation
Recovery with treatment is often possible for many of
the symptoms, although treating patients with Refsum dis-
ease cannot reverse damage to the eyesight and hearing.
Clinical trials
The National Institute for Neurological Diseases and
Stroke and the National Institutes of Health supports re-
search to help increase understanding and awareness or
Refsum disease, as well as to find new prevention, treat-
ments, or a cure for this disorder. One study, which is
LetterR.qxd 10/1/04 11:08 AM Page 720
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
721
Repetitive motion disorders
aimed at determining the effectiveness of an oral bile acid
therapy regimen is currently recruiting patients with the
infantile form of Refsum disease. (Contact information:
Kenneth Setchell, Study Chair, Children’s Hospital Med-
ical Center, Cincinnati OH; (513) 636-4548).
Prognosis
The prognosis for Refsum disease is highly variable.
Without treatment, the prognosis is poor. In patients who
are treated appropriately, many neurological symptoms
and ichthyosis (scaly, dry skin) generally disappear.

Resources
BOOKS
Iocn Health Publications. The Official Parent’s Sourcebook on
Refsum Disease: A Revised and Updated Directory for the
Internet Age. San Diego: Icon Group International, 2002.
PERIODICALS
Richterich, R., P. van Mechelen, and E. Rossi. “Refsum’s dis-
ease (heredopathia atactica polyneuritiformis): An inborn
error of lipid metabolism with storage of 3,7,11,15-
tetramethylhexadecanoic acid.” Am J Med 39: 230–41.
OTHER
“NINDS Refsum Disease Information Page.” National Institute
of Neurological Disorders and Stroke. (March 10, 2004).
< />refsum_doc.htm>.
ORGANIZATIONS
National Organization for Rare Disorders (NORD). P.O. Box
1968 (55 Kenosia Avenue), Danbury, CT 06813-1968.
(203) 744-0100 or (800) 999-NORD (6673); Fax: (203)
798-2291. <http://
www.rarediseases.org>.
National Tay-Sachs and Allied Diseases Association. 2001
Beacon Street Suite 204, Brighton, MA 02135. (617) 277-
4463 or (800) 90-NTSAD (906-8723; Fax: (617) 277-
0134. <>.
Bryan Richard Cobb, PhD
Repetitive stress injuries see Repetitive
motion disorders
❙
Repetitive motion disorders
Definition

Repetitive motion disorders are a group of syndromes
caused by injuries to muscles, tendons, nerves, or blood
vessels from repeated or sustained exertions of different
body parts. Most of these disorders involve the hands,
arms, or neck and shoulder area. Other names for repeti-
tive motion disorders include repetitive trauma disorders,
repetitive strain injuries (RSIs), overuse syndrome, work-
related disorders, and regional musculoskeletal disorders.
Description
Repetitive motion disorders are characterized by
pain, loss of strength and coordination, numbness or tin-
gling, and sometimes redness or swelling in the affected
area. The symptoms come on gradually, and are usually re-
lieved temporarily by resting or avoiding the use of the af-
fected body part. Repetitive motion disorders are
commonly thought of as work related, but they can occur
as a result of academic, leisure-time, or household activi-
ties as well.
Demographics
The demographics of repetitive motion disorders vary
according to the specific syndrome. As of 2004, about
50% of all industrial injuries in the United States and
Canada are attributed to overuse disorders. Professional
athletes, dancers, and musicians experience one of these
disorders at a much higher percentage at some point in
their careers. The Institute of Medicine’s 2001 study, Mus-
culoskeletal Disorders and the Workplace, reported that
nearly a million American workers were treated in 1999
for work-related pain or impaired function in the arms,
hands, or back. Other experts estimate that overuse in-

juries cost the United States economy between $27 million
and $45 million every year.
Race is not known to be a factor in repetitive motion
disorders. Gender has a significant effect on the demo-
graphics of some disorders, but it is not clear whether the
higher incidence of some disorders in women reflects dif-
ferent occupational choices for men and women, or
whether it reflects biological differences. For example, de
Quervain’s syndrome is a common overuse disorder in
women involved with childcare, because repeated lifting
and carrying of small children places severe strains on the
wrist joint. On the other hand, some researchers think that
the greater frequency of this disorder in women is related
to the effects of female sex hormones on connective tissue,
as women’s ligaments are slightly looser during pregnancy
and at certain points in the menstrual cycle.
Some repetitive motion disorders appear to be age re-
lated. Carpal tunnel syndrome is more common in mid-
dle-aged than in younger women, and trigger finger is
most common in people aged 55–60. It is not yet known
whether the widespread use of computers in the workplace
will change the age distribution of repetitive motion dis-
orders as present workers grow older.
LetterR.qxd 10/1/04 11:08 AM Page 721
722
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
Repetitive motion disorders
The Industrial Revolution led to increased job specialization, which meant that more and more workers were employed
doing one task repeatedly rather than many different tasks. Office work is a case in point. (© Photo Reasearchers.
Reproduced by permission.)

Causes and symptoms
SOFT TISSUE DAMAGE Repetitive motion disorders
are the end result of a combination of factors. One basic
cause of repetitive motion disorders, however, is micro-
traumas, which are tiny damages to or tears in soft tissue
that occur from routine stresses on the body or repeated
use of specific muscles and joints. When microtraumas are
not healed during sleep or daily rest periods, they accu-
mulate over time, causing tissue damage, inflammation,
and the activation of pain receptors in peripheral nerves.
NERVE COMPRESSION Some repetitive motion disor-
ders are associated with entrapment neuropathies, which
are functional disorders of the peripheral nervous sys-
tem. In an entrapment neuropathy, a nerve is damaged by
compression as it passes through a bony or fibrous tunnel.
Carpal tunnel syndrome, de Quervain’s syndrome, ulnar
nerve syndrome, and thoracic outlet syndrome are ex-
amples of entrapment neuropathies.
Compression damages peripheral nerves by limiting
their blood supply. Even slight pressures on a nerve can
limit the flow of blood through the smaller blood vessels
surrounding the nerve. As the pressure increases, trans-
mission of nerve impulses is affected and the patient’s sen-
sation and coordination are affected, with further increases
in nerve compression producing greater distortion of
sensation and range of motion.
TECHNOLOGICAL AND SOCIAL FACTORS Economic
and social factors that have affected people’s occupations
and leisure-time activities over the past two centuries have
contributed to the increase in repetitive motion disorders.

The Industrial Revolution led to increased job specializa-
tion, which meant that more and more workers were em-
ployed doing one task repeatedly rather than many
different tasks. In addition, industrialization brought about
the invention of complex tools and machinery that affect
the tissues and organs of the human body in many ways.
LetterR.qxd 10/1/04 11:08 AM Page 722
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
723
Repetitive motion disorders
The high levels of psychological and emotional tension in
modern life also contribute to repetitive stress injuries by
increasing the physical stresses on muscles and joints.
INDIVIDUAL RISK FACTORS Risk factors that are
associated with repetitive stress injuries include the
following:
• Awkward or incorrect body postures. Each joint in the
body has a position within its range of motion in which
it is least likely to become injured. This position is called
the neutral position. Any deviation from the neutral po-
sition puts increased strain on body tissues. Inadequate
work space, using athletic or job-related equipment that
is not proportioned to one’s height, or improper technique
are common reasons for RSIs related to body posture.
• Use of excessive force to perform a task. Pounding on
piano keys or hammering harder than is necessary to
drive nails are examples of this risk factor.
• Extended periods of static work. This type of work re-
quires muscular effort, but no movement takes place. In-
stead, the muscles contract, preventing blood from

reaching tissues to nourish the cells and carry away
waste products. Over time, the muscle tissue loses its
ability to repair microtraumas. Examples of static work
include sitting at a desk for hours on end or holding the
arms over the head while painting a ceiling.
• Activities that require repetitive movements. Assembly-
line work and word processing are examples of job-re-
lated repetitive motion. In addition, such leisure-time
activities as knitting, embroidery, gardening, model con-
struction, golf or tennis, etc. can have the same long-term
effects on the body as work-related activities.
• Mechanical injury. Tools with poorly designed handles
that cut into the skin or concentrate pressure on a small
area of the hand often contribute to overuse disorders.
• Vibration. There are two types of vibration that can cause
damage to the body. One type is segmental vibration,
which occurs when the source of the vibration affects
only the part of the body in direct contact with it. An ex-
ample of segmental vibration is a dentist’s use of a high-
speed drill. Overexposure of the hands to segmental
vibration can eventually damage the fingers, leading to
Raynaud’s phenomenon. The second type is whole-body
vibration, which occurs when the vibrations are trans-
mitted throughout the body. Long-distance truckers and
jackhammer operators often develop back injuries as the
result of long-term whole-body vibration.
• Temperature extremes. Cold temperatures decrease
blood flow in the extremities, while high temperatures
lead to dehydration and rapid fatigue. In both cases,
blood circulation is either decreased or redirected, thus

slowing down the process of normal tissue recovery.
• Psychological stress. People who are worried, afraid, or
angry often carry their tension in their neck, back, or
shoulder muscles. This tension reduces blood circulation
in the affected tissues, thus interfering with tissue re-
covery. In addition, emotional stress has been shown to
influence people’s perception of physical pain; workers
who are unhappy in their jobs, for example, are more
likely to seek treatment for work-related disorders.
• Structural abnormalities. These abnormalities include
congenital deformities in bones and muscles, changes in
the shape of a bone from healed breaks or fractures, bone
spurs, and tumors. Overdevelopment of certain muscle
groups from athletic workouts may result in entrapment
neuropathies in the shoulder area.
• Other systemic conditions or diseases. People with such
disorders as rheumatoid arthritis (RA), joint infections,
hypothyroidism, or diabetes are at increased risk of de-
veloping repetitive motion disorders. Pregnancy is a risk
factor for overuse disorders affecting the hands because
of the increased amount of fluid in the joints of the wrists
and fingers.
Symptoms
The symptoms of repetitive motion disorders include
the following:
• Pain. The pain of an RSI is typically felt as an aching
sensation that gets worse if the affected joint(s) or limb
is moved or used. The pain may be severe enough to
wake the patient at night.
• Paresthesias. Paresthesia refers to an abnormal sensation

of pricking, tingling, burning, or “insects crawling be-
neath the skin” in the absence of an external stimulus.
• Numbness, coldness, or loss of sensation occur in the af-
fected area.
• Clumsiness, weakness, or loss of coordination result.
• Impaired range of motion or locking of a joint occur.
• Popping, clicking, or crackling sounds in a joint are
experienced.
• Swelling or redness in the affected area are observed.
Diagnosis
History and physical examination
The diagnosis of a repetitive motion disorder begins
with taking the patient’s history, including occupational
history. The doctor will ask about the specific symptoms
in the affected part, particularly if the patient suffers from
rheumatoid arthritis, diabetes, or other general conditions
as well as overuse of the joint or limb.
The next step is physical examination of the affected
area. The doctor will typically palpate (feel) or press on
LetterR.qxd 10/1/04 11:08 AM Page 723
724
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
Repetitive motion disorders
Key Terms
Alexander technique A form of movement therapy
that emphasizes correct posture and the proper po-
sitioning of the head with regard to the spine.
de Quervain’s syndrome Inflammation of the ten-
dons contained within the wrist, associated with
aching pain in the wrist and thumb. Named for the

Swiss surgeon who first described it in 1895, the syn-
drome is sometimes called washerwoman’s sprain be-
cause it is commonly caused by overuse of the wrist.
Entrapment neuropathy A disorder of the periph-
eral nervous system in which a nerve is damaged by
compression as it passes through a bony or fibrous
passage or canal. Many repetitive motion disorders
are associated with entrapment neuropathies.
Ergonomics The branch of science that deals with
human work and the efficient use of energy, includ-
ing anatomical, physiological, biomechanical, and
psychosocial factors.
Median nerve The nerve that supplies the forearm,
wrist area, and many of the joints of the hand.
Neuropathy Any diseased condition of the nervous
system.
Paresthesia The medical term for an abnormal
touch sensation, usually tingling, burning, or prick-
ling, that develops in the absence of an external stim-
ulus. Paresthesias are a common symptom of
repetitive motion disorders.
Peripheral nervous system The part of the human
nervous system outside the brain and spinal cord.
Raynaud’s phenomenon A disorder characterized by
episodic attacks of loss of circulation in the fingers or
toes. Most cases of Raynaud’s are not work-related;
however, the disorder occasionally develops in work-
ers who operate vibrating tools as part of their job, and
is sometimes called vibration-induced white finger.
Transcutaneous electrical nerve stimulation (TENS)

A form of treatment for chronic pain that involves the
use of a patient-controlled device for transmitting
mild electrical impulses through the skin over the in-
jured area.
Trigger finger An overuse disorder of the hand in
which one or more fingers tend to lock or “trigger”
when the patient tries to extend the finger.
Ulnar nerve The nerve that supplies some of the
forearm muscles, the elbow joint, and many of the
short muscles of the hand.
the sore area to determine whether there is swelling as well
as pain. He or she will then perform a series of maneuvers
to evaluate the range of motion in the affected joint(s), lis-
ten for crackles or other sounds when the joint is moved,
and test for weakness or instability in the limb or joint.
There are simple physical tests for specific repetitive mo-
tion disorders. For example, the Finkelstein test is used to
evaluate a patient for de Quervain’s syndrome. The patient
is asked to fold the thumb across the palm of the affected
hand and then bend the fingers over the thumb. A person
with de Quervain’s will experience sharp pain when the
doctor moves the hand sideways in the direction of the
elbow. Tinel’s test is used to diagnose carpal tunnel syn-
drome. The doctor gently taps with a rubber hammer along
the inside of the wrist above the median nerve to see
whether the patient experiences paresthesias.
Laboratory tests
Laboratory tests of blood or tissue fluid are not ordi-
narily ordered unless the doctor suspects an infection or
wishes to rule out diabetes, anemia, or thyroid imbalance.

Imaging studies
Imaging studies may be ordered to rule out other con-
ditions that may be causing the patient’s symptoms or to
identify areas of nerve compression. When surgery is
being planned, x rays may be helpful in identifying stress
fractures, damage to cartilage, or other abnormalities in
bones and joints. Magnetic resonance imaging (MRI)
can be used to identify injuries to tendons, ligaments, and
muscles as well as areas of nerve entrapment.
Electrodiagnostic studies
The most common electrodiagnostic tests used to
evaluate repetitive motion disorders are electromyogra-
phy (EMG) and nerve conduction studies (NCS). In EMG,
the doctor inserts thin needles in specific muscles and ob-
serves the electrical signals that are displayed on a screen.
This test helps to pinpoint which muscles and nerves are
affected by pain. Nerve conduction studies are done to de-
termine whether specific nerves have been damaged. The
doctor positions two sets of electrodes on the patient’s skin
over the muscles in the affected area. One set of electrodes
LetterR.qxd 10/1/04 11:08 AM Page 724
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
725
Repetitive motion disorders
stimulates the nerves supplying that muscle by delivering
a mild electrical shock; the other set records the nerve’s
electrical signals on a machine.
Treatment team
A mild repetitive motion disorder may be treated by
a primary care physician. If conservative treatment is in-

effective, the patient may be referred to an orthopedic sur-
geon or neurosurgeon for further evaluation and surgical
treatment. Patients whose disorders are related to job dis-
satisfaction, or who have had to give up their occupation
or favorite activity because of their disorder, may benefit
from psychotherapy.
Physical therapists and occupational therapists are an
important part of the treatment team, advising patients
about proper use of the injured body part and developing
a home exercise program. Some patients benefit from
having their workplace and equipment evaluated by the
occupational therapist or an ergonomics expert. Profes-
sional athletes, dancers, or musicians usually consult an
expert in their specific field for evaluation of faulty posture
or technique.
Treatment
Conservative treatment
Conservative treatment for overuse injuries typically
includes:
• Resting the affected part. Complete rest should last no
longer than two to three days, however. What is known
as “relative rest” is better for the patient because it main-
tains range of motion in the affected part, prevents loss
of muscle strength, and lowers the risk of “sick behav-
ior.” Sick behavior refers to using an injury or illness to
gain attention or care and concern from others.
• Applying ice packs or gentle heat.
• Oral medications. These may include mild pain relievers
(usually NSAIDs); amitriptyline or another tricyclic an-
tidepressant; or vitamin B6.

• Injections. Corticosteroids may be injected into joints to
lower inflammation and swelling. In some cases, local
anesthetics may also be given by injection.
• Splinting. Splints are most commonly used to treat over-
use injuries of the hand or wrist; they can be custom-
molded by an occupational therapist.
• Ergonomic corrections in the home or workplace. These
may include changing the height of chairs or computer
keyboards; scheduling frequent breaks from computer
work or musical practice; correcting one’s posture; and
similar measures.
• Transcutaneous electrical nerve stimulation (TENS).
TENS involves the use of a patient-controlled portable
device that sends mild electrical impulses through in-
jured tissues via electrodes placed over the skin. It is re-
ported to relieve pain in 75–80% of patients treated for
repetitive motion disorders.
Surgery
Repetitive motion disorders are treated with surgery
only when conservative measures fail to relieve the pa-
tient’s pain after a trial of six to 12 weeks. The most com-
mon surgical procedures performed for these disorders
include nerve decompression, tendon release, and repair of
loose or torn ligaments.
Complementary and alternative (CAM) treatments
CAM treatments that have been shown to be effective
in treating repetitive motion disorders include:
• Acupuncture. Studies funded by the National Center for
Complementary and Alternative Medicine (NCCAM)
since 1998 have found that acupuncture is an effective

treatment for pain related to repetitive motion disorders.
• Sports massage, Swedish massage, and shiatsu.
• Yoga and tai chi. The gentle stretching in these forms of
exercise helps to improve blood circulation and maintain
range of motion without tissue damage.
• Alexander technique. The Alexander technique is an ap-
proach to body movement that emphasizes correct pos-
ture, particularly the proper position of the head with
respect to the spine. It is often recommended for dancers,
musicians, and computer users.
• Hydrotherapy. Warm whirlpool baths improve circula-
tion and relieve pain in injured joints and soft tissue.
Recovery and rehabilitation
Recovery from a repeated motion disorder may take
only a few days of rest or modified activity, or it may take
several months when surgery is required.
Rehabilitation is tailored to the individual patient and
the specific disorder involved. Rehabilitation programs for
repetitive motion disorders focus on recovering strength in
the injured body part, maintaining or improving range of
motion, and learning ways to lower the risk of re-injuring
the affected part. Professional musicians, dancers, and ath-
letes require highly specialized rehabilitation programs.
Clinical trials
As of early 2004, there were four clinical trials re-
lated to repetitive motion disorders sponsored by the Na-
tional Institutes of Health (NIH) that are recruiting
LetterR.qxd 10/1/04 11:08 AM Page 725
726
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS

Repetitive motion disorders
subjects. One is a comparison of amitriptyline (an antide-
pressant medication) and acupuncture as treatments for
CTS. A second study will evaluate the effectiveness of a
protective brace in preventing overuse disorders associated
with hand-held power tools. The third study will evaluate
the effects of fast-paced assembly-line work on the health
of rural women. The fourth study is a comparison of sur-
gical and nonsurgical treatments for CTS.
Prognosis
The prognosis for recovery from repetitive motion
disorders depends on the specific disorder, the degree of
damage to the nerves and other structures involved, and
the patient’s compliance with exercise or rehabilitation
programs. Most patients experience adequate pain relief
from either conservative measures or surgery. Some, how-
ever, will not recover full use of the affected body part and
must change occupations or give up the activity that pro-
duced the disorder.
Resources
BOOKS
National Research Council and Institute of Medicine (IOM).
Musculoskeletal Disorders and the Workplace: Low Back
and Upper Extremities. Washington, DC: National
Academy Press, 2001.
“Neurovascular Syndromes: Carpal Tunnel Syndrome.” The
Merck Manual of Diagnosis and Therapy, edited by Mark
H. Beers, MD, and Robert Berkow, MD. Whitehouse
Station, NJ: Merck Research Laboratories, 2002.
Pelletier, Kenneth R., MD. The Best Alternative Medicine,Part

II, “CAM Therapies for Specific Conditions: Carpal
Tunnel Syndrome.” New York: Simon & Schuster, 2002.
“Tendon Problems: Digital Tendinitis and Tenosynovitis.” The
Merck Manual of Diagnosis and Therapy, edited by Mark
H. Beers, MD, and Robert Berkow, MD. Whitehouse
Station, NJ: Merck Research Laboratories, 2002.
PERIODICALS
Andersen, J. H., J. F. Thomsen, E. Overgaard, et al. “Computer
Use and Carpal Tunnel Syndrome: A 1-Year Follow-Up
Study.” Journal of the American Medical Association 289
(June 11, 2003): 2963–2969.
Fuller, David A., MD. “Carpal Tunnel Syndrome.” eMedicine
October 15, 2003 (March 23, 2004). <di-
cine.com/orthoped/topic455.htm>.
Hogan, K. A., and R. H. Gross. “Overuse Injuries in Pediatric
Athletes.” Orthopedic Clinics of North America 34 (July
2003): 405–415.
Kale, Satischandra, MD. “Trigger Finger.” eMedicine February
25, 2002 (March 23, 2004). < />orthoped/topic570.htm>.
Kaye, Vladimir, MD, and Murray E. Brandstater, PhD.
“Transcutaenous Electrical Nerve Stimulation.”
eMedicine January 29, 2002 (March 23, 2004).
< />Kern, R. Z. “The Electrodiagnosis of Ulnar Nerve Entrapment
at the Elbow.” Canadian Journal of Neurological
Sciences/Journal canadien des sciences neurologiques 30
(November 2003): 314–319.
Kryger, A. I., J. H. Andersen, C. F. Lassen, et al. “Does
Computer Use Pose An Occupational Hazard for Forearm
Pain; from the NUDATA Study.” Occupational and
Environmental Medicine 60 (November 2003): e14.

Leclerc, A., J. F. Chastang, I. Niedhammer, et al. “Incidence of
Shoulder Pain in Repetitive Work.” Occupational and
Environmental Medicine 61 (January 2004): 39–44.
Meals, Roy A., MD. “De Quervain Tenosynovitis.” eMedicine
April 15, 2002 (March 23, 2004). <http://www.
emedicine.com/orthoped/topic482.htm>
Nourissat, G., P. Chamagne, and C. Dumontier. “Reasons Why
Musicians Consult Hand Surgeons.” [in French] Revue de
chirurgie orthopÈdique et rÈparatrice de l’appareil
moteur 89 (October 2003): 524–531.
Stern, Mark, MD, and Scott P. Steinmann, MD. “Ulnar Nerve
Entrapment.” eMedicine 8 January 2004 (March 23,
2004). < />topic574.htm>.
Strober, Jonathan B., MD. “Writer’s Cramp.” eMedicine
January 18, 2002 (March 23, 2004). <di-
cine.com/neuro/topic614.htm>.
Strum, Scott, MD. “Overuse Injury.” eMedicine September 14,
2001 (March 23, 2004). < />topic97.htm>.
Tallia, A. F., and D. A. Cardone. “Diagnostic and Therapeutic
Injection of the Wrist and Hand Region.” American
Family Physician 67 (February 15, 2003): 745–750.
Valachi, B., and K. Valachi. “Mechanisms Leading to
Musculoskeletal Disorders in Dentistry.” Journal of the
American Dental Association 134 (October 2003):
1344–1350.
OTHER
National Institute of Neurological Disorders and Stroke
(NINDS). NINDS Thoracic Outlet Syndrome Information
Page. (March 23, 2004). < />health_and_medical/disorders/thoracic_doc.htm>.
ORGANIZATIONS

American Academy of Orthopaedic Surgeons (AAOS). 6300
North River Road, Rosemont, IL 60018-4262. (847) 823-
7186 or (800) 346-AAOS; Fax: (847) 823-8125.
<>.
American Society for Surgery of the Hand (ASSH). 6300
North River Road, Suite 800, Rosemont, IL 60018. (847)
384-8300; Fax: (847) 384-1435.
<>.
National Institute for Occupational Safety and Health
(NIOSH). Centers for Disease Control and Prevention,
1600 Clifton Road, Atlanta, GA 30333. (404) 639-3534
or (800) 311-3435. < />homepage.html>.
National Institute of Arthritis and Musculoskeletal and Skin
Diseases (NIAMS) Information Clearinghouse, National
LetterR.qxd 10/1/04 11:08 AM Page 726
GALE ENCYCLOPEDIA OF NEUROLOGICAL DISORDERS
727
Respite
Institutes of Health. 1 AMS Circle, Bethesda, MD 20892-
3675. (301) 495-4844 or (877) 22-NIAMS; Fax: (301)
718-6366. <http://
www.niams.nih.gov>.
National Institute of Neurological Disorders and Stroke
(NINDS). 9000 Rockville Pike, Bethesda, MD 20892.
(301) 496-5751 or (800) 352-9424. <http://
www.ninds.nih.gov>.
Rebecca J. Frey, PhD
❙
Respite
Definition

Respite literally means a period of rest or relief.
Respite care provides a caregiver temporary relief from the
responsibilities of caring for individuals with chronic
physical or mental disabilities. Respite care is often re-
ferred to as a gift of time.
Description
Respite was developed in response to the deinstitu-
tionalization movement of the 1960s and 1970s. Main-
taining individuals in their natural homes rather than
placing them in long-term care facilities was viewed as
beneficial to the individual, the involved family, and soci-
ety (in terms of lowered health care costs). The primary
purpose of respite care is to relieve caregiver stress,
thereby enabling them to continue caring for the individ-
ual with a disability.
Respite care is typically provided for individuals with
disorders related to aging (dementia, frail health), termi-
nal illnesses, chronic health issues, or developmental dis-
abilities. More recently, children with behavior disorders
have also been eligible for respite care. Respite care is usu-
ally recreational and does not include therapy or treatment
for the individual with the disability.
Caregivers frequently experience stress in the forms of
physical fatigue, psychological distress (resentment, frus-
tration, anxiety, guilt, depression), and disruption in rela-
tions with other family members. The emotional aspects of
caring for a family member are often more taxing than the
physical demands. Increased caregiver stress may result in
health problems such as ulcers, high blood pressure, diffi-
culty sleeping, weight loss or gain, or breathing difficulties.

Types of respite
Length of respite care can be anywhere from a few
hours to several weeks. Services may be used frequently
or infrequently, such as for emergencies, vacations, one
day per week or month, weekends, or everyday.
A variety of facilities provide respite care services.
The type of service available is often closely related to the
characteristics of the facility, including:
• In-home respite services consist of a worker who comes
to the family home while the caregiver is away. These
services are usually provided by agencies that recruit,
screen, and train workers. This type of respite is usually
less disruptive to the individual with the disability, pro-
vided there is a good match between the worker and the
individual. However, issues of reliability and trustwor-
thiness of the worker can be an additional source of
stress for the caregiver.
• Respite centers are residential facilities specifically de-
signed for respite care. Adult day care programs and
respite camps also fall into this category. This type of
respite offers more peace of mind to the caregiver, and
may provide a stimulating environment for the individ-
ual with the disability. However, centers usually restrict
length of stay and may exclude individuals based on
severity of disability.
• Institutional settings sometimes reserve spaces to be used
for respite purposes. These include skilled nursing facil-
ities, intermediate care facilities, group homes, senior
housing, regular day care or after-school programs for
children, and hospitals. Some of these facilities provide

higher levels of care, but are less home-like. The indi-
vidual with the disability may oppose staying in an in-
stitutional setting or may fear abandonment.
• Licensed foster care providers can also provide respite
services in their homes.
Funding
Costs of respite care present a financial burden to
many families. Community mental health centers often
fund respite services if the individual meets certain crite-
ria, including eligibility for Medicaid. Wraparound pro-
grams (also accessed through community mental health
centers) for children with emotional or behavioral disor-
ders also pay for respite services. Veteran’s Administration
hospitals provide respite care at little or no charge if the in-
dividual receiving the care is a veteran (but not if the care-
giver is a veteran). Private insurance companies rarely pay
for respite, and many respite providers do not accept this
form of payment. Some respite facilities have sliding-scale
fees. Other facilities operate as a co-op, where caregivers
work at the facility in exchange for respite services.
In addition, respite agencies may have difficulty re-
cruiting and retaining qualified employees, because lim-
ited funding prevents agencies from offering desirable
salaries. The high turnover and unavailability of employ-
ees may result in delays in service delivery or family dis-
satisfaction with services.
LetterR.qxd 10/1/04 11:08 AM Page 727